Clutch with wear compensating releasing spring

ABSTRACT

The invention relates to a vehicle clutch releasing mechanism including a releasing means made of ductile material having both ranges of elastic and plastic deformation and being assembled resiliently and immovably in an axial direction in the clutch engaging state and adapted for positively serving as a pusher of the clutch disc assembly during clutch releasing operation and for compensating wearing amount of clutch facing elements of the clutch disc assembly by its plastic deformation when clutch facing elements wear and for keeping its elastic thrust energy constant, and for limiting the returning of the clutch disc assembly to a constant amount.

Nakane [451 Feb. 12, 1974 CLUTCH WITH WEAR COMPENSATING RELEASING SPRING[75] Inventor: Mototaka Nakane, Hekinan, Japan [73] Assignee: AisinSeiki Kabushiki Kaisha,

Karuja, Aichi pref., Japan 22] Filed: Feb. 23, 1972 21 Appl. No.2228,665

[30] Foreign Application Priority Data Feb. 23, 1971 Japan 46/008782[52] US. Cl 1'92/111 A, 192/70.28, 267/161 [51] Int. Cl. Fl6d 13/75 [58]Field of Search. 192/111 A, 89 R, 70.25, 70.28

[56] References Cited UNITED STATES PATENTS 3,128,862 4/1964 Ludwig...192/70.28

1,768,346 6/1930 Thompson l92/70. 28 X 2,174,316 9/1939 Dunkelow.192/111A X 3,403,755 10/1968 Barrett et al.... 192/111 A X 3,702,651 111972 Fujita et'al 192/111 A x FOREIGN PATENTS OR APPLICATIONS 1,926,4315/1969 Germany l92/70.28

Primary ExaminerBenjamin W. Wyche Attorney, Agent, or FirmOblon, Fisher,Spivak, Mc- Clelland & Maier [57] ABSTRACT The invention relates to avehicle clutch releasing mechanism including a releasing means made ofductile material having both ranges of elastic and plastic deformationand being assembled resiliently and immovably in an axial direction inthe clutch engaging state and adapted for positively serving as a pusherof the clutch disc assembly during clutch releasing operation and forcompensating wearing amount of clutch facing elements of the clutch discassembly by its plastic d o a when 2911 1211 amine. e e w and forkeeping its elastic thrust energy constant, and for limiting thereturning of the clutch disc assembly to a constant amount.

5 Claims, 11 Drawing Figures IIIIIIIIIII.

- PATENTEDFEB 12w 1 3.791.502

"SHEET 1 or e 4 a M 33a PAIENIEUFEB 1 21974 SHEEI 2 0F 6 FIG. 2

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' SHEET 3 or 6 FIG. 31v

PATENIEB FEB I 21914 SHEEI S [If 6 SHEET -6 BF 6 CLUTCH WITH WEARCOMPENSATING RELEASING SPRING BACKGROUND OF THE INVENTION This inventionrelates to improvements in and relating to a vehicle clutch releasingmechanism, especially adapted for use on automotive vehicles.

Generally speaking, conventional vehicle clutch releasing mechanisms arenot presently fitted with positive clutch releasing means for positivelyreleasing a clutch disc plate assembly from engagement with the flywheelfixedly mounted on the input shaft consisting generally of thecrankshaft of the vehicle drive engine. Most conventional clutchreleasing mechanisms rely instead upon negative means such as enginevibration or the like. The clutch disc plate assembly is mounted betweenthe flywheel and an axially shiftable pressure plate and is fitted withfacing elements adapted for engagement with both the flywheel andpressure plate on the one hand, and is mountedthrough a boss axiallyslidably on an output shaft, yet rotatable in unison therewith, on theother hand. This output shaft is arranged concentrically with the inputshaft and is relatively rotatable therewith. Since the clutch disc plateassembly is coupled through a spline connection with the output shaft, asubstantial sliding resistance is encountered thereat, even upon axialmovement of the pressure plate in its clutch releasing direction,resulting in a substantial retardation in the clutch releasing movementof the clutch disc assembly and thus the remainingly effectiveengagement of the clutch facing element with the flywheel therebyinviting an entrained rotation of the assembly. This residual phenomenongives rise to gearing cricks and creep phenomenons of a geartransmission in the related mechanical parts. Further there is noadjusting means in the prior mechanisms in which the returning amount ofthe clutch disc assembly is held constant.

There has been introduced such a vehicle being provided with means formoving the clutch hub to the side of the pressure plate overcoming thesliding resistance at the splined portion of the clutch hub, however,there yet has been no provision of means for limiting the returningamount of the clutch hub or means for constantly pushing the clutch hubback to a certain position. Accordingly, in these means, it is fearedthat the clutch facing element adheres to .the pressure plate when thelever height of a diaphragm spring and the release gap between theclutch facing element and the flywheel are adjusted.

In addition, there has been introduced such a vehicle being providedwith a means for adjusting the returned position of the clutch hub byadjusting the friction force of a friction means being disposed betweena member rotating in unison with the output shaft and the clutch hub andfor pushing back the clutch hub. This friction force varies with theerror introduced in making these members and the qualitativelystabilized friction means could not be mass produced and the means alsoproves very expensive due to the grinding treatment of the friction facethereof necessary for providing the stabilized means. To stabilize thefriction force being caused by the friction means, a means has beenpresented for engagement with the serration provided on the clutch hub,but the regulating amount, however, could be adjusted only by the pitchunit and fine adjustment was. not possible. These deficiencies areconsidered to be greatly disadvantageous in practice.

SUMMARY OF THE INVENTION nism capable of providing a constant gapbetween a flywheel and a clutch facing element upon clutch releaseoperation.

It is a further object of the present invention to provide a unique andhighly simplified releasing mechanism of a friction clutch of thepositively acting type.

The foregoing and other objects are attained according to one aspect ofthe present invention through the provision of a releasing member for avehicle clutch releasing device being formed of a ductile materialhaving both ranges of elastic and plastic deformation and being disposedresiliently and immovably in an axial direction in a clutch engagingstate between an output shaft and a 'clutch hub of a clutch discassembly provided between a flywheel and a pressure plate and mountedaxially slidably on and rotatablywith the output shaft. The releasingmember is operative as a pusher of the clutch disc assembly during aclutch releasing operation through its plastic deformation to insuremoving the clutch disc assembly back away from the flywheel a constantamount regardless of wear of clutch facing elements of the clutch discassembly.

BRIEF DESCRIPTION OF THE DRAWINGS Various other objects, features andattendant advantages of this invention will be more fully appreciatedasthe same becomes better understood from the following detaileddescription when considered in connection with the accompanyingdrawings, wherein like reference numerals designate like orcorresponding parts throughout the several views and in'which: 1

FIG. 1 is substantially a half of an axial section of a first embodimentof the invention wherein the clutch is seen in its engaged position; I

FIG. 2 is a view similar to FIG. 1, wherein, however, the clutch isdisengaged and a clutch releasing mecha-' nism according to thisinvention is brought into actuation;

FIG. 3 is an enlarged front view of the releasing member of theinvention being used in FIG. 1.

FIG. 4 is an enlarged sectional view taken along the line lV-IV of FIG.3;

FIG. 5 is a graph diagrammatically representing the characteristics ofthe releasing member;

FIG. 6 is a view similar to FIG. 1, illustrating however, a secondembodiment of the invention;

. FIG. 7 is a front view of a releasing member of the invention beingused in FIG. 6;

FIG. 8 is a sectional view taken along the line VIII- -VIII of FIG. 7;

FIG. 9 is an enlarged front view of a modification of the releasingmember according to this invention;

:FIG. is an enlarged sectional nemaraaa'ar DESCRIPTION OF THEILLUSTRATED EMBODIMENTS Referring now to FIGS. 1 and 2 of theaccompanying drawings, the first embodiment of the invention will bedescribed hereinbelow in detail.

In these figures, the numberal 10 represents only partially a crankshaftof an internal combustion engine, not shown, fitted on an automotivevehicle, again not shown, an end flange 10a being provided at theillustrated end of the crankshaft and made integral therewith. Aflywheel 11, only partially shown, is concentrically and fixedlyattached to the shaft flange 10a by means of a plurality of fixing boltsof which only one is shown representatively at 12.

Numeral 13 generally represents schematically and only partially acommonly known clutch disc assembly which is normally squeezed betweenthe flywheel 11 and a pressure plate 14, concentrically arranged andonly partially shown, for transmitting drive torque transmitted from theengine crankshaft 10 to a conventional transmission gearing or othermeans, not shown, through an output shaft 15, which also is onlypartially shown.

A conventional cover plate 16, only partially shown, is attachedconcentrically and fixedly to the flywheel 11 by means of a plurality offixing bolts, not shown. Numeral 17 generally represents a diaphragmspring, only partially shown, being mounted on the cover plate 16 bymeans of a plurality of rivet members of which only one is shownrepresentatively at 18. The diaphragm spring 17 exerts an axial pressureupon the pressure plate 14 in its actuating direction.

A first pivot ring 19 formed into a large wire ring is inserted, asshown, between an enlarged head at 18a of the rivet member 18 and thediaphragm spring 17, and in a similar way, a second pivot ring 20 ofsimilar configuration is kept in position between diaphragm spring 17and cover plate 16, so as to maintain the aforementioned relativeposition of the members 16, 17 and 18. These parts are so designed andarranged that the peripheral ring part 17a of the diaphragm spring 17urges the pressure plate 14 by pressure contact with a ringshapedprojection 14a of the pressure plate 14 in the leftward axial direction,as seen in FIGS. 1 and 2, so as to maintain the clutch disc assembly 13in its pressurizedly squeezed position between the flywheel 11 and thepressure plate 14.

Numeral 21 represents a retracting spring, the axially inner part ofwhich is fixedly attached to the outerperiphery of'the pressure plate 14by means of a set screw 22. The axially outer part of the retractingspring 21 represents a semi-circular curved cross-section, as shown, andis kept in pressure contact with the outermost part of the ring-shapedpart 17a of diaphragm spring 17, so as to urge the latter to abutagainst the pressure plate 14. In practice, however, a plurality ofthese retracting springs 21 and the respective fixing screws 22 arearranged radially and separately around the axis X-X' of the mechanism.

When radially and centrally extending arms 17b of the diaphragm spring17, although only one is representatively shown, aresubjected to anaxial pressure by a release bearing23 in clutch release operation, aswill be more fully described hereinafter, the aforementioned pressurecontact between 17a and 14 is overcome and the retracting spring 21through the diaphragm spring part 17a is withdrawn, which will serve forforcibly drawing the pressure plate 14 back towards the cover plate 16.

Numeral 24 represents a conventional disc facing member provided at theflywheel side, and numeral 25 represents a similar member provided atthe pressure plate side. These disc facing members 24 and 25 aresubstantially fixedly attached to the respective sides of a disc spring26 by means of a plurality of fixing rivets of which only one is shownrepresentatively at 27. The inner periphery of the disc spring 26 isfixedly attached as at 28 to a main disc plate 29. The rivets 27 are sodesigned and dimensioned that the members 24 and 25 can move axially andrelative to disc spring 26.

Numeral 30 represents only partially, yet generally,

1 a clutch hub which is formed radially and integrally with a flange 30amounting on its both sides the main disc plate 29 and an auxiliary discplate 31. These plates 29 and 31 are somewhat loosely attached to eachother by means of rivet or other similar means, not shown, and throughan intermediary of a conventional damper unit 32, so as to allow acertain relative rotation therebetween. This damper unit 32 will servefor transmitting torque from the plates 29 and 31 to the clutch hubflange 30a. In practice, however, it should be noted that a plurality ofthese damper units 32, preferably four in number, are arranged radiallywith mutually equal peripheral distance, about the axis X-X'. The clutchhub 30 is axially slidably mounted on output shaft 15 through a splinecoupling shown at 15a formed thereon. The left-hand end of the outputshaft 15 is concentrically and rotatably mounted in the right-hand endof the crankshaft 10 through a pilot bearing 33. A releasing member 34made of ductile material is elastically disposed within a boss 30b ofclutch hub 30 and an inner race 33a of bearing 33. It is desired toconstruct the setting load of the releasing member 34 at a maximumlimiting point of elastic deformation or a range of plastic deformation.

Next, referring toFIGS. 3 and 4, the releasing member 34 is shown beingprovided with three tongue portions 35 symmetrically disposed on theprojecting radially inward from an annular tubular portion 36. A freeend of each tongue portion 35 contacts the inner race 33a of the pivotbearing 33 and the annular portion 36 is fixedly engaged about theperipheral surface of the boss 30b. Each tongue portion 35 has at leastoutstanding characteristics of elastic deformation, as shown by the OPstraight line, and of plastic deformation, as shown by the curved linefollowing the P point, as shown in FIG. 5.

In the clutch engaging state as viewed in FIG. 1, the disc 13 issqueezed between the flywheel 11 and the pressure plate 14 asaforementioned. The tongue portions 35 of the releasing member 24 arecompressed about 0.5mm at the maximum elastic limit P of the tongueportions 35, or against the resilient thrust energy thereof after thislimit P namely, at a range of plastic deformation, so the hub 30 in FIG.1 is moved about 0.5mm to the leftward direction from that in FIG. 2,and the tongue portions 35 receive the acting force of the diaphragmspring 17 being operated through the hub 30 and are compressed until thefacings 24 and 25 are squeezed between the flywheel 11 and the pressureplate 14. This compressing force of the tongue portions 35 will in, turnact as an operating force for forcibly moving the disc 13 to therightward direction upon the clutch releasing operation.

The operation of the releasing mechanism so far shown and described isasfollows:

When the driver of the vehicle depresses the conventional clutch pedal,not shown, the release bearing 23 is shifted axially leftward from itsposition shown in FIG. 1 to that shown in FIG. 2, as may be easilyunderstood by any person skilled in the art. For this purpose, theclutch pedal is operatively connected with the release bearing 23,although the necessary motion transmitting means have not been shown onaccount of its very popularity. By this leftward sliding movement of thebearing 23, the extending arms 17b are caused to shift equally leftwardby contact thereof with the moving or moved bearing 23. Therefore, thediaphragm spring 17 will perform a corresponding swivelling movementabout the pivot rings 19 and 20 as its center, as may be well understoodby comparison of FIG. 2 with FIG. 1. Thus, the ring part 17a of thediaphragm spring 17 so far as it is shown on the drawing will shiftrightward from the position shown in FIG. 1 to that shown in FIG. 2.

In this way, the clutch disc 13 is released from pressure contact by thepressure plate 14. Thus, the clutch disc is freed. With the rightwarddisplacement of the ring part 17a of the diaphragm spring 17, thepressure plate 14 is forcibly moved rightwards by the catching action ofthe retracting springs 21.

Although there is a certain amount'of sliding resistance at the splinecoupling 1511 between the clutch hub 30 and the output shaft 15, theclutch disc 13 is forcibly moved 0.5mm in the rightward direction byvirtue of the resilient axial pressure of the three tongue portions 35against this sliding resistance. It will'be seen that upon the executionof the clutch release in the aforementioned way, the clutch disc 13 cannot be entrained by the rotating flywheel 11 with the engine and itscrankshaft 10 kept in rotation. Under these conditions, therefore, agear shift operation in the transmission gearing can be performed in asmooth manner.

With clutch facings 24 and 25 being subjected to substantial wear aftera substantial service period of the clutch, the clutch disc 13 may begradually moved to the side of flywheel l 1. Therefore, when the stressacting on the tongue portions 35 exceeds a certain value, plasticdeformation of the tongue portions 35 is'caused in accordance with theexceeding amount of said stress by advancement of the disc 13 towardsthe flywheel 11, namely, the tongue portions 35 in which a plasticdeformation has once occurred will offer their returning force to theclutch disc assembly. 13 from a further certain value nearly equal tothat certain value so that the tongue portions 35 keep the returningamount of the clutch hub constant. FIG. 5 shows a stress-distortion lineof the material being used for the releasing member 34 of the invention.It is clear that when the releasing member is made of ductile materialas aforementioned and the ductile material in brief is the same withinits elastic limit as that of general spring material, the amount ofdisplacement of'the beam (tongue portion is as follows:

a, K1214 (r /E h) 8,: returning amount of spring K spring constant Emodulus of elasticity of Youngs modulus L length of beam h thickness ofbeam ar stress within elastic limit 6, distortion within elastic limitThe broken line shows the relation between 0' and a after thedeformation of the beam reaches a point P, namely, after the beam isdeformed by 8.

01, stress within elastic limit after plastic deformation 8 e distortionwithin leastic limit after plastic deformation 8 Thereby, if b is thewidth of beam when the beam is deflected by 6,, a returning force ofspring P acting on the beam is as follows:

Accordingly, if the sliding resistance R at the spline coupling 15abetween the clutch hub 30 and the output shaft 15 is smaller than P,,the clutch releasing operation can be certainly performed. In addition,with wearing of the facings 24 and 25, the clutch hub 30 becomes nearerto the side of the flywheel 11 so that the stress of the tongue portion35 becomes geater and the tongue portion 35 is subject to plasticdeformation when the stress of the tongue portion 35 exceeds the stressof elastic limit 5 In this state 0' is nearly equal to 0' and E isnearly equal to 6 P point is shifted to P, in this time.

The returning amount of the spring 8, after elastic deformation is asfollows:

Consequently the returning amount of the spring 8, is held to be nearlyequal to 8,, even after plastic deformation.

This is to say, the clutch disc 13 is moved toward the flywheel 11 inaccordance with the amount of wearing of the facings 24 and 25, and inthat time, the amount of movement of the clutch disc 13 and the force ofthe spring are kept constant, respectively, at any wearing stage of thefacings so that there is no accidental chance for the facing 25 adheringto the pressure plate 14 and the disc 13 making retrained rotation withthe flywheel 11. Therefore, the clutch release operation can beperformed in a smooth way.

Next, referring to FIGS. 6, 7 and 8, the second embodiment of theinvention will now be described hereinbelow in detail.

This embodiment however, shows a releasing member 37 being equipped withthe clutch of a front engine and a front-driving type. The output shaft15 and the crankshaft 10 are concentrically arranged in this clutchtype, and the crankshaft 10 has no pilot bearing 33 for supporting theoutput shaft 15 as in the foregoing embodiment of FIG. 1. The releasingmember 37 is provided with three tongue portions 38 and a circular disccrankshaft 10 by a woodruff key 43. Numeral 44 is a screw member forpreventing axial withdrawal of the sleeve 41 from the crankshaft 10.

In this embodiment, the construction of the releasing member 37 and theoperation thereof are substantially the same as in FIG. 1 so that thedescription thereabout will be omitted.

Referring now to FIGS. 9 and 10, a releasing member 45 is a thirdmodification, the condition of the attachment and the operation thereofbeing the same as those of FIG. 1. The releasing member 45 is providedwith an outer stepped annular tubular portion 46 and four leg portions47 inwardly extending from the portion 46 with an inner end of each legportion 47 being formed integrally with an inner tubular portion 48. Theouter stepped annular tubular portion 46 of the releasing member 45 isfixedly connected to the boss 30b of the clutch hub 30 and the innertubular portion 48 is contacted with'the inner race 33a of the pilotbearing 33 the same as in FIG. 1. The construction and the operation ofthe releasing member 45 are the same as those in FIG. 1 so that furtherexplanation may be omitted.

STill referring to FIGS. 9 and 10, the specification of the releasingmember 45 is as follows: A=30mm in diameter, B=l6mm, C=l6mm., D=2mm.,E=0.5mm. and the material thereof is SPCD (Japanese IndustrialStandards). Referring to FIG. 11, the experimental results of thereleasing member 45 in FIGS. 9 and 10 are shown, and it is seen' thataccording to the increase of the displacement 8 from O to Q the load Wacting on the inner tubular portion 48 is increased, while however, theload, W is decreased to Q when the displacement 8 is increased after Qand once the lead W is decreased from O to Q and Q.,, the displacement 8is decreased from The load W is increased from Q, to

Q when the displacement 8 is again increased. Then, the load W isdecreased when the displacement 8 is increased after Q' Accordingly, aline connecting the points 0, Q Q Q and Q represent one cycle, anothercycle is shown by a line connecting the points 0,, Q',, 0' and Q,, and afurther cycle is shown by a line connecting the points, 0' 0",, Q" Q";,and 0",, the cycles depicting continuous performaance. A locus of thepoints Q Q2, Q'1 0'2, Q"1 an 0 2 m y be described as an imaginaryparabola and each of the points 0,, Q 0,, Q' Q" and is positioned on animaginary straight line seen as being just a little above the 0 level.

By these experimental results the following features are proved: first,that it is capable of obtaining a normally certain amount ofdisplacement 6 according to wearing of the clutch facing elements 24 and25 being caused by repetition from clutch engaging operation to clutchdisengaging operation and vice versa, because in the displacement 8, adifference between 0 and Q;, is nearly equal to .a difference between 0'and 0' which is nearly equal to a difference between 0" and Q";,. Also,while the load W is decreased from O to Q when the displacement 8 isdecreased from Q it is still a fact that the load W at this time acts onthe releasing member 45. Therefore, if the resisting force at the splinecoupling 15a is kg, the lead W which is being applied from the point 0the load of which is 21 .Skg to the resisting force, i.e., 5kg, acts onthe releasing member 45 as an operating force for returning the clutchdisc assembly 13 from the flywheel l l, and it is surely capable ofdisengaging the clutch.

Accordingly, by utilizing the aforedescribed releasing members made ofat least SPCD having both plastic and elastic deformation, it ispossible to provide both functions of positively returning the clutchdisc assembly 13 and of compensating for wear on the friction elements24 and 25 thereof.

Obviously many changes and modifications of the present invention arepossible in light of the foregoing teachings. It is to be understood,therefore, that within the scope of the appended claims, the inventionmay be practiced otherwise than as specifically described herein.accordingly,

What is claimed as new and desired to be secured by letters patent ofthe united states is:

1. A vehicle clutch releasing mechanism comprising:

A crankshaft being driven with an engine;

a flywheel fixedly mounted on said crankshaft;

a cover plate fixedly attached to said flywheel;

a pressure plate mounted'axially and slidably on said cover plate androtatable in unison with said cover plate;

an output shaft mounted on and rotatable relative to said crankshaft;

a clutch disc assembly provided between said flywheel and said pressureplate and mounted axially slidably on and rotatably in unison with saidoutput shaft, said disc assembly being. provided with a pair of facingelements at each side thereof;

said mechanism being characterized by the provision of a releasing meanshaving tongue portions and an annular portion integral therewith beingcoaxially disposed about saidoutput shaft between said crankshaft andsaid clutch disc assembly and being made of a ductile material havingboth ranges of elastic and plastic deformation and being assembledresiliently and immovably in an axial direction in the clutch engagingslate, and adapted for positively urging said clutch disc assembly tomove toward said pressure plate during clutch releasing operation andfor compensating for the wearing amount of said clutch facing elementsby said plastic deformation in dependence upon the wear of said clutchfacing elements.

2. The vehicle clutch releasing mechanism as set forth in claim 1,characterized by an end of each tongue portion being contacted with aninner race of a pilot bearing being provided on said output shaft forsupporting an end thereof, while said annular portion is fixedlycontacted with a clutch hub comprising in said clutch disc assembly.

3. A vehicle clutch releasing mechanism comprising:

a crankshaft being driven with an engine;

a flywheel fixedly mounted on said crankshaft;

a cover plate fixedly'attached to said flywheel;

a pressure plate mounted axially and slidably on said cover plate androtatable in unison with said cover plate; I

an output shaft mounted on and rotatable relative to said crankshaft;

a clutch disc assembly provided between said flywheel and said pressureplate and mounted axi ally slidably on and rotatably in unison with saidoutput shaft, said disc assembly being provided with a pair of facingelements of each side thereof;

said mechanism being characterized by the provision of a releasing meanshaving tongue portions and a circular disc portion integral therewithbeing coaxially disposed about said output shaft between said crankshaftand said clutch disc assembly and being made of a ductile materialhaving both ranges of elastic and plastic deformation and beingassembled resiliently and immovably in an axial direction in the clutchengaging state, and adapted for positively urging said clutch discassembly to move toward said pressure plate during clutch releasingoperation and for compensating for the wearing amount of said clutchfacing elements by said plastic defonnation in dependence upon the wearof said clutch facing elements. 4. The vehicle clutch releasingmechanism as set forth in claim 3, characterized by an end of eachtongue portion being contacted with said output shaft,

'while said circular disc portion is fixedly connected with a clutch hubcomprised in said clutch disc assembly.

5. A vehicle clutch releasing mechanism comprising:

a crankshaft being driven ,with an engine;

a flywheel fixedly mounted on said crankshaft;

a cover plate fixedly attached to said flywheel;

a pressure plate mounted axially and slidably on said cover plate androtatable in unison with said cover plate; w

an output shaft mounted on and rotatable relative to said crankshaft;

a clutch disc assembly provided between said flywheel and said pressureplate and mounted axially slidably on and rotatably in unison with saieoutput shaft, said disc assembly being provided a with a pair of facingelements at each side thereof;

said mechanism being characterized by the provision of a releasing meanshaving an outer stepped annular tubular portion, an inner tubularportion and leg portions being disposed between said outer and innertubular portions, said outer and inner tubular portions said legportions being formed integrally with each other, and being coaxiallydisposed about said output shaft between said crankshaft and said clutchdisc assembly and being made of a ductile material having both ranges ofelastic and plastic deformation and being assembled resiliently andimmovably in an axial direction in the clutch engaging state, andadapted for positively urging said clutch disc assembly to move towardsaid pressure plate during clutch releasing operation and forcompensating for the wearing amount of said clutch facing elements bysaid plastic deformation in dependence upon the wear of said clutchfacing elements.

1. A vehicle clutch releasing mechanism comprising: A crankshaft beingdriven with an engine; a flywheel fixedly mounted on said crankshaft; acover plate fixedly attached to said flywheel; a pressure plate mountedaxially and slidably on said cover plate and rotatable in unison withsaid cover plate; an output shaft mounted on and rotatable relative tosaid crankshaft; a clutch disc assembly provided between said flywheeland said pressure plate and mounted axially slidably on and rotatably inunison with said output shaft, said disc assembly being provided with apair of facing elements at each side thereof; said mechanism beingcharacterized by the provision of a releasing means having tongueportions and an annular portion integral therewith being coaxiallydisposed about said output shaft between said crankshaft and said clutchdisc assembly and being made of a ductile material having both ranges ofelastic and plastic deformation and being assembled resiliently andimmovably in an axial direction in the clutch engaging slate, andadapted for positively urging said clutch disc assembly to move towardsaid pressure plate during clutch releasing operation and forcompensating for the wearing amount of said clutch facing elements bysaid plastic deformation in dependence upon the wear of said clutchfacing elements.
 2. The vehicle clutch releasing mechanism as set forthin claim 1, characterized by an end of each tongue portion beingcontacted with an inner race of a pilot bearing being provided on saidoutput shaft for supporting an end thereof, while said annular portionis fixedly contacted with a clutch hub comprising in said clutch discassembly.
 3. A vehicle clutch releasing mechanism comprising: acrankshaft being driven with an engine; a flywheel fixedly mounted onsaid crankshaft; a cover plate fixedly attached to said flywheel; apressure plate mounted axially and slidably on said cover plate androtatable in unison with said cover plate; an output shaft mounted onand rotatable relative to said crankshaft; a clutch disc assemblyprovided between said flywheel and said pressure plate and mountedaxially slidably on and rotatably in unison with said output shaft, saiddisc assembly being provided with a pair of facing elements of each sidethereof; said mechanism being characterized by the provision of areleasing means having tongue portions and a circular disc portionintegral therewith being coaxially disposed about said output shaftbetween said crankshaft and said clutch disc assembly and being made ofa ductile material having both ranges of elastic and plastic deformationand being assembled resiliently and immovably in an axial direction inthe clutch engaging state, and adapted for positively urging said clutchdisc assembly to move toward said pressure plate during clutch releasingoperation and for compensating for the wearing amount of said clutchfacing elements by said plastic deformation in dependence upon the wearof said clutch facing elements.
 4. The vehicle clutch releasingmechanism as set forth in claim 3, characterized by an end of eachtongue portion being contacted with said output shaft, while saidcircular disc portion is fixedly connected with a clutch hub comprisedin said clutch disc assembly.
 5. A vehicle clutch releasing mechanismcomprising: a crankshaft being driven with an engine; a flywheel fixedlymounted on said crankshaft; a cover plate fixedly attached to saidflywheel; a pressure plate mounted axially and slidably on said coverplate and rotatable in unison with said cover plate; an output shaftmounted on and rotatable relative to said crankshaft; a clutch discassembly provided between said flywheel and said pressure plate andmounted axially slidably on and rotatably in unison with saie outputshaft, said disc assembly being provided with a pair of facing elementsat each side thereof; said mechanism being characterized by theprovision of a releasing means having an outer stepped annular tubularportion, an inner tubular portion and leg portions being disposedbetween said outer and inner tubular portions, said outer and innertubular portions said leg portions being formed integrally with eachother, and being coaxially disposed about said output shaft between saidcrankshaft and said clutch disc assembly and being made of a ductilematerial having both ranges of elastic and plastic deformation and beingassembled resiliently and immovably in an axial direction in the clutchengaging state, and adapted for positively urging said clutch discassembly to move toward said pressure plate during clutch releasingoperation and for compensating for the wearing amount of said clutchfacing elements by said plastic deformation in dependence upon the wearof said clutch facing elements.